In February, the leaders expressed concern that DHS had only requested half the normal flight hours from the Department of Defense to support Operation Phalanx, despite a full appropriation of funds from Congress.

At this time, DHS has not requested any flight hours to support Operation Phalanx for calendar year 2017, according to a news release.

“Given the continuing surge of migrants along the Southern Border beyond FY15 numbers and a large uptick in apprehensions already for the month of November 2016, we believe DHS should be requesting more surveillance and security resources, not less,” Abbott, Cornyn and Cuellar write in the letter.

“Given that Customs and Border Protection’s (CBP) Office of Air and Marine is currently 12 percent below its goal for air interdiction agents this cut in DoD support is extremely imprudent,” they added.

Abbott, Cornyn and Cuellar requested that DHS identify which resources will be utilized to back fill the gaps left by a reduction in the aerial resources used to support the nation’s border security efforts.